A judge on Monday acquitted a Salvadoran man of criminal charges after a trial that followed allegations from his lawyers that he was the victim of police brutality at the time of his March arrest in Westbury.

Nassau County District Court Judge Sharon Gianelli found William Guillen, 33, of Hicksville, not guilty of a harassment violation along with misdemeanor charges of assault and resisting arrest -- charges that already had been reduced after what began as a felony case.

In delivering her verdict, Gianelli said from the bench in Hempstead that "the law does not require the police to always be right," but requires them to "be reasonable."

"It is precisely this requirement . . . that provides the tenuous balance between the onerous burden that the police have to protect and serve . . . and the right of the individual to be free from excessive intrusiveness on the part of the police," she said.

Guillen's attorney, Amy Marion of Garden City, called it a "tragedy" that her client -- who also has an immigration hold -- has been jailed for months. She previously filed a notice of claim against the county alleging Guillen was the victim of excessive force, civil rights violations and false arrest.

"Thankfully, we had a judge who really looked at the law," Marion said, adding that much of the trial revolved around police officers' credibility, and "three of them admitted making false statements."

The Nassau district attorney's office said at trial that police who were staking out an area by a Hispanic restaurant because of drug complaints approached Guillen after seeing him in what looked like a drug deal. A prosecutor said Guillen bit a sergeant's leg and police had to hit him to force him to unclamp his teeth as he violently resisted arrest.

Police had alleged they saw Guillen drop what an officer believed was a bag of cocaine as he ran away, but they didn't recover it due to traffic at the scene.

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The defense claimed Guillen, who speaks little English, mistook the police for robbers. They claimed he never bit the sergeant, had just left a restaurant to pick up more food nearby and later suffered broken ribs and other injuries as a result of a police beating.

A Nassau police spokesman declined to comment after the verdict, citing an ongoing internal investigation. A district attorney's office spokesman also declined to comment.

Guillen's other attorney, Karen Bobley of Mineola, previously called for a federal probe, claiming police should face criminal charges.

Edgar Vasquez, consul general of El Salvador for Long Island, was in court Monday with Guillen's other supporters.

"This is the way the law is supposed to work," Vasquez said, before referencing Guillen's quest to stay in the United States as "the second battle."

"I'm happy to see that he's free of these charges," Yanira Pleites, the mother of Guillen's infant daughter, said through a Spanish-language interpreter.

Guillen smiled at supporters who softly applauded the verdict, before heading back to jail because of his immigration detainer. His lawyers said he illegally crossed into the United States in 2002, but they are fighting -- along with other advocates -- for him to stay in the country.